package ca.scotthyndman.as2haxe.dom;

/**
 * Descriptor for a simple property of an AST node. A simple property is one
 * whose value is a primitive type (such as <code>int</code> or
 * <code>boolean</code>) or some simple value type (such as
 * <code>String</code> or <code>ASInfixExpression.Operator</code>), or an
 * ASTNode that should not be treated as a child.
 */
public final class ASSimplePropertyDescriptor extends ASPropertyDescriptor {

	/**
	 * Value type. For example, for a node type like SingleVariableDeclaration,
	 * the modifiers property is int.class
	 */
	private final Class valueType;

	/**
	 * Indicates whether a value is mandatory. A property value is allowed to be
	 * <code>null</code> only if it is not mandatory.
	 */
	private final boolean mandatory;

	/**
	 * Creates a new simple property descriptor with the given property id. Note
	 * that this constructor is declared package-private so that property
	 * descriptors can only be created by the AST implementation.
	 * 
	 * @param nodeClass
	 *            concrete AST node type that owns this property
	 * @param propertyId
	 *            the property id
	 * @param valueType
	 *            the value type of this property
	 * @param mandatory
	 *            <code>true</code> if the property is mandatory, and
	 *            <code>false</code> if it is may be <code>null</code>
	 */
	ASSimplePropertyDescriptor(Class nodeClass, String propertyId,
			Class valueType, boolean mandatory) {
		super(nodeClass, propertyId);
		if (valueType == null) {
			throw new IllegalArgumentException();
		}
		this.valueType = valueType;
		this.mandatory = mandatory;
	}

	/**
	 * Returns the value type of this property.
	 * <p>
	 * For example, for a node type like SingleVariableDeclaration, the
	 * "modifiers" property returns <code>int.class</code>.
	 * </p>
	 * 
	 * @return the value type of the property
	 */
	public Class getValueType() {
		return this.valueType;
	}

	/**
	 * Returns whether this property is mandatory. A property value is not
	 * allowed to be <code>null</code> if it is mandatory.
	 * 
	 * @return <code>true</code> if the property is mandatory, and
	 *         <code>false</code> if it is may be <code>null</code>
	 */
	public boolean isMandatory() {
		return this.mandatory;
	}
}
